Once you leave, it's back to causing blackouts because you wanted to recharge your seaglide batteries. But you can't really even unlock it until you're already about to beat the game without sequence breaks, essentially. While you are down there you won't have to worry about power so it's worth building for your last 10 minute drive between the lava castle and the containment facility. It's only useful (in an honest non exageration sense) when you are in the lava biomes.
